Many researchers believe that physics will not be complete until it can explain not just the behaviour of space and time, but where these entities come from.

Imagine waking up one day and realizing that you actually live inside a computer game, says Mark Van Raamsdonk, describing what sounds like a pitch for a science-fiction film. But for Van Raamsdonk, a physicist at the University of British Columbia in Vancouver, Canada, this scenario is a way to think about reality. If it is true, he says, everything around us  the whole three-dimensional physical world  is an illusion born from information encoded elsewhere, on a two-dimensional chip. That would make our Universe, with its three spatial dimensions, a kind of hologram, projected from a substrate that exists only in lower dimensions.

This 'holographic principle' is strange even by the usual standards of theoretical physics. But Van Raamsdonk is one of a small band of researchers who think that the usual ideas are not yet strange enough. If nothing else, they say, neither of the two great pillars of modern physics  general relativity, which describes gravity as a curvature of space and time, and quantum mechanics, which governs the atomic realm  gives any account for the existence of space and time. Neither does string theory, which describes elementary threads of energy.

Van Raamsdonk and his colleagues are convinced that physics will not be complete until it can explain how space and time emerge from something more fundamental  a project that will require concepts at least as audacious as holography. They argue that such a radical reconceptualization of reality is the only way to explain what happens when the infinitely dense 'singularity' at the core of a black hole distorts the fabric of space-time beyond all recognition, ...

The thing about cosmology is that no one is really an expert. The biggest difference between a duffer and a PhD theoretical Physicist when it comes to cosmology is that the Physicist knows how to make his ideas sound sophisticated - he knows the language of his trade. But the ideas are only marginally more likely to be right.

18
posted on 08/28/2013 4:44:05 PM PDT
by John Valentine
(Deep in the Heart of Texas)

In 2006, Ashtekar and his colleagues reported7 a series of simulations that took advantage of that fact, using the loop quantum gravity version of Einstein's equations to run the clock backwards and visualize what happened before the Big Bang. The reversed cosmos contracted towards the Big Bang, as expected. But as it approached the fundamental size limit dictated by loop quantum gravity, a repulsive force kicked in and kept the singularity open, turning it into a tunnel to a cosmos that preceded our own.

This year, physicists Rodolfo Gambini at the Uruguayan University of the Republic in Montevideo and Jorge Pullin at Louisiana State University in Baton Rouge reported a similar simulation for a black hole. They found that an observer travelling deep into the heart of a black hole would encounter not a singularity, but a thin space-time tunnel leading to another part of space.

I found this fascinating. I have for years thought that the singularity before the Big Bang must have been very much like a Black Hole. This reinforces that theory.

In these two simulations both the singularity prior to the Big Bang and the singularity of a Black Hole become tunnels. It could simply be that both simulations have a common or different mathematical errors that lead to this tunnel effect but I find it intriguing.

20
posted on 08/28/2013 4:58:19 PM PDT
by Pontiac
(The welfare state must fail because it is contrary to human nature and diminishes the human spirit.)

Some interesting pull-quotes & observations from the various sections in the article: [i]f theories cannot be tested, then to me, they are not science. They are just religious beliefs, and they hold no interest for me. The reversed cosmos contracted towards the Big Bang, as expected. But as it approached the fundamental size limit dictated by loop quantum gravity, a repulsive force kicked in and kept the singularity open, turning it into a tunnel to a cosmos that preceded our own... [a]n observer travelling deep into the heart of a black hole would encounter not a singularity, but a thin space-time tunnel leading to another part of space. It is early days and our job is hard because we are fishes swimming in the fluid at the same time as trying to understand it, [a]dding causality changed everything. After all, says Loll, the dimension of time is not quite like the three dimensions of space. We cannot travel back and forth in time, she says. So the team changed its simulations to ensure that effects could not come before their cause  and found that the space-time chunks started consistently assembling themselves into smooth four-dimensional universes with properties similar to our own... [s]ome suggest that the appearance of dark energy is a sign that our Universe is now growing a fourth spatial dimension. [t]he three-dimensional universe is being held together by quantum entanglement on the boundary  which means that in some sense, quantum entanglement and space-time are the same thing.

The biggest difference between a duffer and a PhD theoretical Physicist when it comes to cosmology is that the Physicist knows how to make his ideas sound sophisticated - he knows the language of his trade.

Rather simplistic and naïve.

The difference between a duffer and a PhD theoretical Physicist is mathematics.

A theoretical Physicist cosmologist can test his theory with mathematical models. A sound cosmological theory will have a mathematical model that will confirm or disprove its possibility. If the mathematics determine that the theory is possible then a physical experiment can be designed to test the theorys relationship to the real world.

A duffer would be hard pressed to design a mathematical model to demonstrate that the universe resides on the back of a turtle or any other theory he may dream up and be harder pressed to design an experiment to provide physical proof to backup that theory.

25
posted on 08/28/2013 5:21:04 PM PDT
by Pontiac
(The welfare state must fail because it is contrary to human nature and diminishes the human spirit.)

But I did say that the physicist knows the language of his trade. Maybe you didn’t understand what I was getting at, but that language IS mathematics.

I will disagree with you on one point: mathematical models will NOT always prove or disprove a theory. They will ten k to confirm or disconfirm, but the mathematics is always also subject to inspection and investigation. The history of physics is replete with theories once confirmed by mathematical models which were later shown - both the theory and the model - to be incomplete or inadequate.

My point was and is that cosmology is supremely speculative.

27
posted on 08/28/2013 5:29:18 PM PDT
by John Valentine
(Deep in the Heart of Texas)

I think it is standard relativity theory that time dilation depends on the (location and velocity of the) observer. The passage of time as seen from earth today would likely differ from the passage of time as seen by an observer at the time and location of the big bang. Could 15 billion years be consistent with 6 thousand years? Maybe so.

29
posted on 08/28/2013 6:21:30 PM PDT
by ChessExpert
(The unemployment rate was 4.5% when Democrats took control of Congress in 2006.)

Another freeper posted the article and we both came to the conclusion that determining the age depends on whose perspective one is looking from.....anyone outside time and space (God) or those inside time and space (us, angels, demons).

A theoretical Physicist cosmologist can test his theory with mathematical models. A sound cosmological theory will have a mathematical model that will confirm or disprove its possibility. If the mathematics determine that the theory is possible then a physical experiment can be designed to test the theorys relationship to the real world.

One of the fundamental problems with modern physics IMO is that they are chasing down the 'string theory' rabbit hole. String theory isn't even wrong, and pretty much can't really be tested.

the trouble is that something like string theory appears to mathematically beautiful to many physicists but it is neither prescriptive or descriptive of reality. That is, the math doesn’t describe any part of visible reality nor can the math be used to solve real life problems.

I have a way of explaining inflation without breaking the speed limit. Id like to fly it by someone skilled in the art in private so I dont embarrass my self in public with an obvious mistake...

Trust me. If you are able to offer up any sort of explanation for faster than light expansion of the universe then you qualify for immunity from embarrassment. Why don't you post a short sketch of your idea?

They argue that such a radical reconceptualization of reality is the only way to explain what happens when the infinitely dense 'singularity' at the core of a black hole distorts the fabric of space-time beyond all recognition, ...

After playing softball yesterday morning, me and my fellow seniors were sitting at the picnic table, eating chips and drinking beer when that very subject came up........what a coincidence.

One of the fundamental problems with modern physics IMO is that they are chasing down the 'string theory' rabbit hole. String theory isn't even wrong, and pretty much can't really be tested.

Pretty much my take on String Theory as well. I keep hoping that there will be a breakthrough one way or the other. Some smart guy/gal needs to find experimental confirmation that String Theory is the right track or, in some way, prove it isn't.

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